We have the following indirect implication of form equivalence classes:
| Implication | Reference |
|---|---|
| 123 \(\Rightarrow\) 62 |
Two model theoretic ideas in independence proofs, Pincus, D. 1976, Fund. Math. |
| 62 \(\Rightarrow\) 102 | The Axiom of Choice, Jech, 1973b, page 162 problem 11.12 |
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement |
|---|---|
| 123: | \(SPI^*\): Uniform weak ultrafilter principle: For each family \(F\) of infinite sets \(\exists f\) such that \(\forall x\in F\), \(f(x)\) is a non-principal ultrafilter on \(x\). |
| 62: | \(C(\infty,< \aleph_{0})\): Every set of non-empty finite sets has a choice function. |
| 102: | For all Dedekind finite cardinals \(p\) and \(q\), if \(p^{2} = q^{2}\) then \(p = q\). Jech [1973b], p 162 prob 11.12. |
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